Addition product of diester of dithiophosphoric acid and maleic acid and its esters, and method of preparation



Patented Dec. 18, 1951 ADDITION PRODUCT OF DIESTER OF DI- THIOPHOSPHORICACID AND MALEIC ACID AND ITS ESTERS, AND METHOD OF PREPARATION Jack '1.Cassaday, Stamford, Conn., assignor to American Cyanamld Company, NewYork, N. Y., a corporation of Maine No Drawing. Application March 2,1950, Serial No. 147,325

Claims.

in which R1 and R2 are chosen from the group consisting of aliphatic andaromatic hydrocarbon radicals, and R3 and R4 are chosen from the groupconsisting of hydrogen, aliphatic and aromatic hydrocarbon radicals.

In the new compounds the R's may be the same or different radicals, andwhen they stand for aliphatic radicals it is to be understood that theyrepresent both the straight chain and branch chain, the saturated andunsaturated, and the cycloaliphatic hydrocarbon radicals. Typicalexamples of these radicals are methyl, ethyl, npropyl, isopropyl,n-butyl, isobutyl, sec.-amyl, n-hexyl, 2-ethyl-hexyl, n-octyl, n-decyl,n-dodecyl, oleyl, cetyl, ceryl, allyl, cyclohexyl, phenyl, and naphthyl.

These phosphate esters may be readily prepared by reacting an acidphosphate of the formula 1in which R1 and R2 have the meaning shownabove, with an unsaturated compound of the formula in which R3 and R4have the meaning shown above.

A typical reaction in which 0,0-dimethyl dithiophosphoric acid isreacted with diethyl maleate to produce S-(1,2-dicarbethoxyethyl)0,0-dimethyl dithiophosphate may be illustrated as follows:

f 3110000111. CHO/ HCOOCaHl crno s i -scnoooo,m

omo H.000 0.11

The unsaturated compounds utilized in the present process may be eithermalelc acid, the

acid maleate esters, the neutral maleate esters,

or their isomers, fumaric acid, the acid fumarate esters and the neutralfumarate esters. Therefore, it is to be understood that the formulaonoooR.

cnoooR.

used in this specification and the appended claims is intended torepresent both the maleate and fumarate compounds.

When one or both of the reactants are solids, the reaction is preferablycarried out in the presence of a solvent. Such solvents include the lowmolecular weight aliphatic monohydric alcohols, the ketones such as, Iorexample, acetone, methyl ethyl ketone, methyl 'isobutyl ketone, methylbenzyl ketone, cyclohexanone, acetophenone, and the like; aliphaticesters such as ethyl acetate, amyl acetate, Z-ethylhexyl acetate, methylpropionate, methyl butyrate, ethyl butyrate, and isopropyl butyrate;dioxane, benzene, nitrobenzene, chlorobenzene, toluene, xylene,chlorororm, carbon tetrachloride, 1,2-dimethoxyethane, and the trialkylphosphates such as trimethyl phosphate, triethyl phosphate, andtriisopropyl phosphate.

The reaction is preferably carried out at a temperature within the rangeof from about 20 to 150 C. However, temperatures outside of this rangemay be employed depending upon the type of reactants and solventsutilized.

The reaction may be accelerated by using an aliphatic tertiary aminecatalyst, such as for example triethylamine, triisopropylamine,tri-nbutylamine, tri-Z-ethylhexylamine, and the like. The amount ofcatalyst employed is usually within the range of from 0.2% to 2.0%,based on the total weight of the reactants.

An anti-polymerization agent such as hydroquinone may be employed toguard against polymerization of the maleate or fumarate compound.

The following examples will further illustrate the invention.

Example 1 A mixture of 108 g. of 0,0-diethyl dithiophosphoric acid, 86g. of diethyl fumarate, and 0.2 g. of hydroquinone was heated at C. for24 hours, then allowed to cool to room temperature. The reaction mixturewas taken up in 300 cc. of benzene, washed with 10% sodium carbonatesolution and with water. The organic layer was dried over anhydroussodium sulfate, filtered, and concentrated in vacuo. The residue,S-(1,2-dicarbethoxyethyl) 0,0-diethyl dithiophosphate, was a colorlessliquid, having a refraetive index a 1.4895. weighing 170 g. (94% 1 (1).

Example 2 72 g. of dimethyl maleate was added in small portions to amixture of 94.5 g. of 0,0-dimethyl dithiophosphoric acid, 1 cc. oftrie'thylamine, and 0.5 g. of hydroquinone. Cooling was applied asneeded to keep the temperature of the reaction mixture below 60C. Afterthe initial exothermic reaction had subsided, the mixture was heated at65 C. for 16 hours, allowed to cool to room temperature, and dissolvedin benzene. The benzene solution was washed with sodium carbonatesolution and with water. The

v organic layer was dried over anhydrous sodium sulfate, filtered, andheated in vacuo to remove the benzene. oxyethyl 0,0-dimethyldithiophosphate. was a clear colorless liquid having a refractive indexa 1.5080, weighing 138 g. (91% yield.)

Example 3 The procedure of Example 2 was employed using 34.4 g. ofdiethyl fumarate. 37.8 g. of 0,0- dimethyl dithiophosphoric acid, 0.3cc. of triethylamine, and 0.2 g. of hydroquinone. 50.8 g. (77% yield) ofS-(1,2-dicarbethoxyethyl) 0,0-dimethyl dithiophosphate was obtained. Theproduct was a colorless liquid having a refractive index 11 1.4970.

Example 4 The procedure of Example 2 was employed.

using 40 g. of diisopropyl maleate, 40 g. of 0,0- dimethyldithiophosphoric acid, 0.5 cc. of triethylamine, and 0.2 g. ofhydroquinone. The

reaction mixture was heated at 65 C. for 24" hours. 63 g. (88% yield) ofS-(L2-dicarbisopropoxyethyl) 0,0 dimethyl dithiophosphate was obtained.The product was a clear pink liquid having a refractive index n 1.4862.

Example 6 I The procedure of Example 2 was employed using 72 g. ofdimethyl maleate, 108 g. of 0,0- diethyl dithiophosphoric acid, 1 cc. oftriethylamine. and 0.2 g. of hydroquinone. The reaction mixture washeated at 65 C. for 24 hours. 155.5 g. (94% yield) ofS-(1,2-dicarbomethoxyethyl) 0,0-diethyl dithiophosphate was obtained.The product was a colorless liquid having a refractive index 11 1.4970.

Example 7 The procedure of Example -2 was employed using 86 g. ofdiethyl furnarate, 111 g. of 0,0- diethyl dithiophosphoric acid, 1 cc.of triethylamine, and 0.2 g. of hydroquinone. 165 g. (92% yield) ofS-(1,2-dicarbethoxyethyl) 0,0-diethyl dithiophosphate was obtained. Theproduct was a colorless liquid having a refractive index a 1.4887.

The residue, S-(1,2-dicarbometh-' Emample 8 A mixture of 24.1 g. ofbis(2-chioroethyl) fumarate, 22.3 g. of 0,0-diethyl dithiophosphoricacid, 50 cc. of xylene, 0.3 cc. of triethylamine, and 0.2 g. ofhydroquinone was heated at 65 C. for a period of 84 hours. The reactionmixture was cooled to room temperature, diluted with 50 cc. of xylene,washed with 5% sodium carbonate solution and with water. ganic layer wasdried over Drierite, filtered, and heated in vacuo to remove the xylene.The residue, S {1,2 bis[carbo(2 chloroetho'xyH- ethyl} 0,0-diethyldithiophosphate, was a pale yellow liquid having a refractive index 111.5110 weighing 31.9 g. (75% yield).

Example 9 Example 10 The procedure of Example 2 was employed using 40 g.of diisopropyl maleate, 43.2 g. of 0,0-diethyl dithiophosphoric acid,0.5 cc. of triethylamine, and 0.2 g. of hydroquinone. The reactionmixture was heated at 65 C. for 24 hours. 76 g. (98% yield) ofS-(1,2-dicarbisopropoxyethyl) 0,0-diethyl dithiophosphate was obtained.The product was a pale yellow liquid having a refractive index 111.4805.

Example 11 39.2 g. of diallyl maleate was added slowly to a mixture of44.5 g. of 0,0-diethyl dithiophospho'ric acid, 0.5 cc. of triethylamine,and 0.5 g. of hydroquinone. After a mildly exothermic reaction hadsubsided, the mixture was heated at 65 C. for 16 hours. The reactionmixture was cooled to room temperature, washed with 5% sodium carbonatesolution and with water, dried over Drierite, and filtered to give 31.4g. of S-(LZ-dicarballoxyethyl) 0.0-diethyl dithiophosphate, a colorlessliquid having a refractive index 11 1.5000.

Example 12 The procedure of Example-11 was employed using 22.8 g. ofdi-n-butyl fumarate, 22 g. of 0,0-diethy1 dithiophosphoric acid, 0.3 cc.of triethylamine, and 0.2 g. of hydroquinone. The reaction mixture washeated at 65 C. for 21 hours. 31 g. (75% yield) ofS-(1,2-dicarbo-n-butoxy ethyl) 0,0-diethyl dithiophosphate was obtained.The product was a colorless liquid having a refractive index 11 1.4814.

Example 13 The procedure of Example 11 was employed using 22.8 g. ofdiisobutyl. fumarate, 22 g. of 0,0-diethyl dithiophosphoric acid, 0.3cc. of triethylamine, and 0.2 g. of hydroquinone. The reaction mixturewas heated at 65 C. for 24 hours. 25.3 g. (61% yield) ofS-(1,2-dicarbisobutoxyethyl) 0,0-diethyl dithiophosphate was obtained.The product was a colorless liquid having a refractive index n 1.4793.

The or- Example 14 Example 15 The procedure of Example 2 was employedusing 45.2 g. of bis(2-butyloctyl) maleate, 22.3 g. of 0,0-diethyldithiophosphoric acid, 0.5 cc. of triethylamine, and 0.2 g. ofhydroquinone. 58.1 g. (91% yield) of S-{1,2-bis[carbo(2-butyloctyloxy)]ethyl} 0,0-diethyl dithiophosphate was .obtained. The product was aclear yellow liquid having a refractive index a 1.4755.

Example 16 The procedure of Example 2 was employed using 26.8 g. ofdiphenyl fumarate, 22.3 g. of 0,0-diethyl dithiophosphoric acid, 1 cc.of triethylamine, and 1 g. of hydroquinone. The reaction mixture washeated at 65 C. for a period of 76 hours. 41 g. (90% yield) ofS-(1,2-dicarbophenoxyethyl) 0,0-diethyl dithiophosphate was obtained.The product was a viscous brown liquid.

Example 17 The procedure of Example 2 was employed using 17.2 g. ofdiethyl fumarate, 23.5 g. of 0.0- diisopropyl dithiophosphoric acid, 0.5cc. of triethylamine, and 0.5 g. of hydroquinone. The reaction mixturewas heated at 65 C. for 18 hours. 34.0 g. (88% yield) ofS-(1,2-dicarbethoxyethyl) 0,0-diisopropyl dithiophosphate was obtained.The product was a colorless liquid having a refractive index 11 1.4811.

Example 18 The procedure of Example 2 was employed using 11.2 g. ofdiethyl fumarate, 28 g. of 0,0-din-decyl dithiophosphoric acid, 0.2 cc.of triethylamine, and 0.2 g. of hydroquinone. The reaction mixture washeated at 65 C. for 23 hours. 33.5 g. (88% yield) ofS-(1,2-dicarbethoxyethyl) 0,0-di-n-decyl dithiophosphate was obtained.The product was a pale yellow liquid having a refractive index a 1.4769.

Example 19 The procedure of Example 14 was employed using 17.2 g. ofdiethyl fumarate, 32.3 g. of 0,0- diphenyl dithiophosphoric acid, 150cc. of benzene, 0.3 g. of triethylamine, and 0.2 g. of hydroquinone. Thereaction mixture was allowed to stand at room temperature for a periodof 7 days. 33 g. (83% yield) of S-(l,2-dicarbethoxyethyl) 0,0-diphenyldithiophosphate was obtained. The product was a pale brown liquid havinga refractive index a 1.5532.

Example 20 A mixture of mono-2-ethylhexyl maleate (0.50 mol) and0,0-diethyl dithiophosphoric acid (0.52 mol) was heated at 93-94 C. for6 hours, and then allowed to stand at room temperature for 16 hours.Titration of a portion of the product 6 with 0.1 N sodium hydroxideindicated the reaction to be 99% complete. The product was a yellow,viscous liquid.

Example 21 A mixture of mono-n-octadecyl maleate (0.20 mol) and0,0-diethyl dithiophosphoric acid (0.21 mol) was heated at C. for 4hours. Titration of a portion of the product with 0.1 N sodium hydroxideindicated the reaction to be 97% complete. The product was a yellow,viscous liquid.

The phosphate esters of the present invention are adapted for varioususes. more particularly as insecticides, and in this connection showremarkably low warm-blooded animal toxicity. They are also useful asfungicides, plasticizers, corrosion inhibitors, flotation agents, andpetroleum additives.

While the invention has been described with particular reference tospecific embodiments, it is to be understood that it is not to belimited thereto but is to be construed broadly and restricted solely bythe scope of the appended claims.

I claim: 1. Phosphate esters of the general formula mo s i -s-on c o 0B.

R: 0 HgC 0 0 B4 s-onc 0 OR:

R20 H30 0 CR4 in which R1 and R: are chosen from the group consisting ofaliphatic hydrocarbon and aromatic hydrocarbon radicals, and R3 and R4are chosen from the group consisting of hydrogen, aliphatic hydrocarbonand aromatic hydrocarbon radicals,

which includes the step of reacting an acid phosphate of the generalformula v i -sn 330 in which R1 and R: are chosen from the groupconsisting of aliphatic hydrocarbon and aromatic hydrocarbon radicals,with an unsaturated compound of the general formula oncooai in which R:and R4 are chosen from the group consisting of hydrogen, aliphatichydrocarbon and aromatic hydrocarbon radicals.

8. The method of claim 7 in which the reacapnoea tion is carried out inthe presence of an aliphatic tertiary amine catalyst. REFER cum The th rclaim); n which t The following references are of record in the tion iscarried out in the presence of a. solvent. me Of this P t 10. The method01 claim '7 in which the. reac- I UNITED STATES \p ms tion is carriedout at a temperature within the Number Name mm 7 ranae of from about20C.to150 C. 2,528,132 A fine Nov. 7. mm

JACK T. CASSfADAY.

1. PHOSPHATE ESTERS OF THE GENERAL FORMULA